Egg-cellent Research

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Zoo InternQuest is a seven-week career exploration program for San Diego County high school juniors and seniors.  Students have the unique opportunity to meet professionals working for the San Diego Zoo, Safari Park, and Institute for Conservation Research, learn about jobs, and then blog about their experience online.  Follow their adventure here!

Did you know that eggs can be used for more than just cooking or eating scrambled on toast? Surprisingly, eggs are one of the most important things in Scientist Dr. Tom Jensen’s job. Dr. Jensen specializes in birds, and works in the Reproductive Physiology Division at the Beckman Center. Reproductive physiology is the study of reproductive organs, hormones, and fertility. Dr. Jensen has a keen interest in bird eggs, not for their uses in recipes, but for their ability to preserve endangered birds. Through a complicated process that transfers gonadal stem cells from exotic bird species to chicken embryos, Dr. Jensen and his team of three students are working on preserving the sperm of valuable exotic species.

Many of you are probably wondering what all of this means, so let me break it down for you. Gonadal stem cells are self-renewing cells located in the gonads of exotic bird species that produce eggs and sperm. As part of Dr. Jensen’s research, these stem cells are taken from male exotic birds that have died from natural causes, and are inserted into fertilized chicken embryos. The stem cells then travel through the tiny blood vessels of the chicken embryo until they reach the gonadal ridge, which is the precursor to the genitals. When the rooster becomes an adult, he will produce both chicken and exotic bird sperm because of the injection of exotic bird gonadal stem cells he received as an embryo. This way, scientists have a ready source of exotic bird sperm to use for artificial insemination.

The process of inserting the exotic bird sperm into the embryo is, in my opinion, the coolest part of the job. It involves sanding a hole in an egg, carefully peeling back the eggshell membrane with tiny tweezers, and using a thin needle to inject stem cells into the embryo. While I didn’t get to inject precious stem cells into an embryo, my fellow interns and I all got a chance to sand a fertilized egg and peel the eggshell membrane to take a look at a live chicken embryo. While it was daunting to sand a hole in a baby chicken’s shell and peel back the shell membrane, it was worth the effort when we saw the embryo and watched its tiny heart beat in our hands. The needle Dr. Jensen uses to inject stem cells is thinner than a strand of his hair. The stem cells injected are fluorescent, so their movements through the blood vessels and into the gonadal ridge can be tracked. Once the injection is completed, Dr. Jensen simply tapes the hole closed and puts the egg back into its incubator to continue developing.

While the workings of the Reproductive Physiology Division at the Beckman Center are complicated, Dr. Jensen was able to teach us the basics of his stem cell research in an understandable and enjoyable way.  Using fertilized chicken eggs and stem cells, Dr. Jensen can increase the reproductive lifespan of an endangered bird well past its death. As Dr. Jensen said of his research, “It’s egg-cellent!”

Thalia, Real World Team
Fall 2012, week six